When filing documents, be they loose sheets, brochures or the like, it is habitual to use file folders which constitute a kind of portfolio, with a front wall, a rear wall and a spine, so that to the internal face of the rear wall and in the proximity of the spine, a support is fastened provided with a plurality of openable rings, so that by perforating marginally and conveniently the sheets or documents to be filed, these can be coupled to the aforementioned rings, when these are open, and be secured when they are closed.
Independently of the high cost of these mechanisms, the fundamental problem with said type of file folders is centred on the fact that the documents must support the forces applied during their manipulation inside the portfolio through the narrow borders defined between their holes and the proximate and corresponding edge, whereby tearing occurs frequently in such documents which, besides signifying a deterioration in the same, sometimes causes their escape or detachment from the file folder.
In an endeavour to overcome this problem, the use is known of adhesive rings to strengthen the holes in the sheets, which constitutes a very complicated and difficult to manage solution and, in a more habitual fashion, fitting the rings of the file folder with a page press, with a means for locking which presses the marginal area of the sheets against the back wall of the portfolio and which, as a consequence, prevents the tensile stress on the sheets from concentrating on their fastening holes, which solution makes the cost of said type of file folder still higher.